Novel high explosive compositions



April 16, 196s Filed Nov.

FREQUENCY 5 Sheets-Sheet l INVENTORS am w sa/o-A/FFL am @0A/Aw Pem/ MAPV/A/ IVI. FE/A/ BMM April 16, 1968 lD. D.. PERRY ET AL 3,378,416

NOVEL HIGH EXPLOSIVE COMPOSITIONS SONVlUWSNVHl April 16, 1968 D. D. PERRY ET AL 3,378,416

NOVEL HIGH EXPLOSIVE COMPOSITIONS BONVLUWSNVH United States Patent O 3,318,416 NOVEL HIGH EXPLOSIVE COMPOSITIONS Donald D. Perry, Morristown, and Marvin M. Fein, Westeld, NJ., and Carl W. Schoenfeldcr, Livermore, Calif.,

assignors, by mesne assignments, to the United States of America as represented by the United States Atomic Energy Commission Filed Nov. 13, 1963, Ser. No. 324,169 46 Claims. (Cl. 149-22) This invention concerns the preparation of explosive mixtures of polynitro organics and organic boron compounds.

More particularly, this invention relates to the preparation of explosive compositions prepared by the in situ reaction of polynitroaliphatic compounds with one or more carboranes or carborane derivatives.

The term carborane(s) as used throughout this application refers to aliphatic compounds containing at least one radical of the formula:

R-C C-R1 \J/ BioHiu wherein R and R1 which can be the same or different are selected from the group consisting of alkyl, alkenyl, and hydroxyalkyl radicals, within the molecule.

While there is no paucity of solid high explosives, there is a need for high explosives which are liquid at -ambient temperatures. Particularly valuable would be liquid state explosive mixtures, having a high brissance which Would become increasingly detonation sensitive with the passage of time yet whose components would be indivi-dually innocuous prior to mixing. This type of liquid explosive would have value in several types of commercial and military applications where solid explosives cannot effectively be used. For example, in mining and quarrying operations, there is frequently a need to implant a high exploy sive charge in narrow crevices, cracks or lissures where no solid charge could be inserted without markedly enlarging the opening. The enlargement of these openings is not only time-consuming and expensvie, but it increases the possibility of accidental landslides and cave-ins. Furthermore, all of the commercially available explosives so`id or liquid form require some type of device usually electrically actuated, to detonate the explosive charge. These devices are expensive and rather complex in structure. Since the environment in which the detonating device functions is usually one of low temperatures and extreme humidity, electrical failure or malfunction is not uncommon. For these purposes liquid state explosives which spontaneously detonate with the passage of time would -be most useful.

Similarly, the above described, contemplated liquid explosive mixtures would be especially suitable for tactical military operations. For example, in guerrilla or partisan warfare a liquid explosive mixture which could be carried incorispicuously in 'bottles or other non-metallic containers would be most useful. Since the liquid components of the explosive mixture are metal-free and could be stored in non-metallic containers, detection by presently used electronic means would be virtually impossible. In addition, unlike solid form explosives, those explosives would not require bulky or intricate detonating devices which are difficult for partisans to obtain. An additional asset of this type of liquid explosive mixture would be in the innocuousness of the individual reactants. None of the uncombined reactants are sensitive to detonation by shock yet the combined reactants rapidly become hypersensitive to shock, eventually auto-detonating with the passage of time. Further the brissance of the mixed explosive reaction mixture is equivalent to TNT.

ICC

While certain liquid form high explosives have been available commercially for some time they possess certain disadvantages which has restricted their general use and made them inapplicable for military use. For example, nitroglycerine, a well-known liquid explosive is extremely sensitive to shock, degrades upon exposure to humidity and has a very low freezing point of 13.1 C. In addiion it has the added disadvantage of having too Igreat a shattering power for some purposes. Finally it requires a detonating device for initiation.

Within recent years, liquid explosive compositions containing polynitroaliphatics have been suggested. These compositions while an improvement over nitroglycerine have certain inherent defects which have restricted their widespread use. These prior art compositions are `best exemplified by tetranitromethane or a comparable polynitrated compound combined with hydrocarbons such as kerosene, gasoline or hydrocarbon deriva-tives including `carbon bisulphide. The prior art compositions particularly those based upon tetranitromethane mixtures are disadvantageous in several respects. For example, the components of the mixture interact chemically when stored for any prolonged period of time and the explosive thereby loses a large proportion of its effectiveness. Furthermore, the stored explosive becomes highly sensitive to detonation by shock. In addition the tetranitromethane based explosive mixtures of the prior art are classified only as medium strength explosives and do not possess the shattering force frequently required. Another shortcoming of the tetranitromethane explosives mixtures of the prior art is they normally contain a large proportion of low boiling `constituents which makes them troublesome to store and handle. Finally, like nitroglycerine and conventional solid form explosives the polynitroalkane explosive mixtures of the prior art require the use of a detonating device to It is a further object of this invention to prepare novel Y polyntroaliph-atic based high explosive compositions.

It is a further object of this invention to prepare autodetonating tetranitrornethane `based explosives which o'bviate the need for detonating devices.

Finally it is an object of this'invention to prepare an explosive mixture whose individual components can be safely stored prior to use and which can be activated when needed at the blasting site.

These objects among many other are achieved by the novel process of this invention to be described below.

In practice one or more polynitroaliphatic reactants are combined with one or more carborane reactants in a suitable container and mixed to a homogeneous reaction mixture using a stream of inert gas or a conventional mixing means. Ordinarily the container is the fissure, crack or crevice where the explosive is to be implanted- Since'the invention is susceptable to various modifications, a more detailed discussion is submitted.

Reactants.-The polynitro reactants of this invention can consist of one or more compounds of diverse origin. For example, the reactants can be highly puried polynitro compounds or the nitration mixtures of substance Where 2 or more hydrogens are replaced by NO2 groups. Within the term polynitro aliphatic( s) as used throughout this application is included the polynitroparans such as the di, triand tetranitroparains as well as the di, tri, and tetranitrated esters of aliphatic alcohols, aliphatic glycols and aliphatic polyglycols. Illustrative examples of these compounds are dinitromethane, dinitroethane, the dinitropropanes, the dinitrobutanes, the dinitropentanes,

trinitromethane, trinitroethane, the trinitropropanes, the trinitrobutanes, the trinitropentanes, tetranitromethane, tetranitroethane, the tetranitropropanes, the tetranitrobutanes, the tetranitropentanes, tetranitrodiglycerin, pentaerythritol tetranitrate and the like. Many of the polynitroaliphatic reactants particularly tetranitromethane are commercially available substances or can be made by the exhaustive vapor or liquid phase nitration of the alkanes at relatively elevated temperatures. The tetranitrodiglycerin is made by the esterication of diglycerol using a mixture of concentrated sulfuric and nitric acids. Similarly pentaerythritol tetranitrate can be produced by nitration with the same mixed acid. Tetranitromethane is the preferred tetranitroalkane reactant because of the explosive potency it contributes to the explosive mixtures, as well as its commercial availability, low cost and relative insensitivity toward detonation.

The carboranes which can be used as co-reactants range from liquids to solids and can be employed either in the purified state or in the form of their reaction mixtures. While generally all of the carboranes or substituted carboranes are satisfactory reactants, the most superior results are obtained when the alkylcarboranes or the hydroxylalkylcarboranes are utilized as reactants. Especially preferred because of their superior performance and ease of preparation are the monoand bis-alkyl and alkenylcarboranes, hydroxyalkylcarboranes. Especially preferred are these same carboranes having from 2-12 carbon atoms. These carborane reactants are preferred because of their ease of preparation coupled with their high explosive performance. Illustrative carboranes which can be used as reactants include among others the simplest member of the series carborane, alkylcarboranes such as methylcarborane, ethylcarborane, n-propylcarborane, isopropylcarborane, n-butylcarborane, the isobutylcarboranes, n-pentylcarborane, the isopentylcarboranes, n-hexylcarborane, the isohexylcarboranes, and the like, the normal and isoalkenylcarboranes such as vinylcarborane, the propenylcarboranes, the butenylcarboranes, the pentenylcarboranes, the hexenylcarborancs, etc., and the hydroxylcarboranes such as hydroxylmethcarborane, hydroxy-nbutyl carboranes and the like as well as the corresponding bis esteried derivatives. These latter compounds include 11,12 bis(trifluoracetoxymethyl)carborane, 11,12 bis(trichloracetoxymethyl)carborane among others. The carborane reactants such as the alkylcarboranes or alkenylcarboranes can be prepared among other ways by contacting the appropriate alkylor alkenylacetylene with decaborane in the environment of Lewis Base(s) at elevated temperatures until the BwHlO moiety is taken up into the molecule. Typical Lewis bases which can be used include among other acetonitrile, diethylsulde, triphenylphosphine, dimethylcyanamide N,Ndimethyl(acetamide) and the like. Carborane can be prepared analogously by the direct reaction of ether solutions of decarborane and acetylene in the presence of diethylsulfide. A preparation of 11,12 bis(hydroxy1nethyl) carborane is given in S.N. 149,484, tiled Oct. 30, 1961. The higher 11,12 bis(hy droxyalkyl) carboranes can be prepared by analogous methods using homologous reactants. The ll-hydroxymethylcarborane can be prepared by interacting decarborane with propargyl acetate in the presence of a Lewis base followed by subsequent hydrolysis in an aqueous media. Again, the higher 1l-hydroxyalkylcarboranes can be prepared by using a longer chain acetylenic reactant instead of propargyl acetate. The esters of the hydroxycarboranes or the hydroxyalkylcarboranes are made by contacting an excess of the appropriate acid or acid anhydride with the hydroxyl containing molecule until substantial quantities of the esters are formed. As is the case in any esterification, catalysts and/or elevated temperatures may be used to accelerate the formation of the described ester(s).

ADJUVANTS The term adjuvants as used throughout this disclosure is the generic designation given to conditioning agents, modifying agents, inhibiting agents, solvents, surface active agents and the like which can be added to the explosive reaction mixtures. These adjuvants while not necessary for an explosive mixture can sometimes be effectively used. When the adjuvants are used they can comprise from 0 to 7 mole percent of the nal explosive composition.

An important class of adjuvants are the lower mononitrated parains particularly nitromethane. These mononitrated paraflins act to inhibit or delay the formation of some of the more detonation sensitive reaction mixtures. The use of these retardants or inhibitors makes it possible to formulate auto-explosive composition with practically any degree of shock sensitivity. In addition, these substances may also serve to promote the solubility of the carboranes in the polynitrated aliphatic co-reactant.

MIXING OF COMPONENTS Most of the polynitrated aliphatic-carborane explosive mixtures become increasingly detonation sensitive with time in the absence of inhibitors. For this reason a means of assuring homogeneity quickly is of importance. A convenient means of producing the required homogeneous explosive mixture is accomplished by bubbling a stream of inert gas through the reaction mixture until a uniform reaction mixture results. Suitable inert gases which can be used in addition to air include argon, neon, nitrogen, carbon dioxide, and the like as well as mixtures of these gases with themselves and/or air. In partisan warfare conditions, the CO2-air mixture exhaled in respiration may be used to supply the inert gas mixture required for mixing. This can be accomplished by blowing through a hollow tube extending into the reaction mixture. Where less detonation sensitive systems are prepared, glass, ceramic or metallic containers can be used to contain the reaction mixtures. In these instances conventional mixing means such as power driven impellers, propellcrs or magnetic stirrers and the like can be used.

DETONATION OF THE EXPLOSIVE MIXTU RES One of the salient advantages of the inventive explosive mixtures is that no detonating device is needed to explode many of the reaction mixtures. These reaction mixtures auto-detonate with the passage of time. In those instances where experience has shown that detonating means are necessary any small detonator is satisfactory. For example, a detonator referred to in the blasting art as a #8 blasting-cap is satisfactory. No booster charge is needed. The detonator when required is placed in the explosive charge container usually prior to addition of one or both of the reactants.

MECHANISM, REACTION PRODUCTS AND STOICHIOMETRY The mechanism by which the reaction mixtures of this invention are formed has not been established at this time. Furthermore, the system can be balanced to favor the formation of CO2 or CO. The stoichiometry of the system will therefore be dependent upon which product is to be produced as well as the reactants used. For this reason, no mechanism or hypotheses is advanced at this time nor is any required stoichiometric ratio of reactants postulated. However, explosive mixtures can ordinarily be produced when as little as 1/5 of the theoretical stoichiometry is followed up to as much of an excess as 2 times of the theoretical stoichiometric amounts. Ordinarily the preferred ratios range between .95 to 1.05 of the theoretical stoichiometric ratios. In some cases stable reaction products are formed and their structure can be indicated by infra-red analysis. Examples of these are where polyntrated alkanes such as tetranitromethane are combined with members of the lower alkenylcarboranes such as the propenylor butenylearboranes. lnfra-red analysis of these reactions indicate the formation of more stable compositions containing 4 nitro groups, (NO2)4, with the concurrent disappearance of the alkenyl unsaturation in the molecule. Although, as indicated above, the structure of the resultant explosive products is largely unknown, it has been determined that products possessing high explosive forces can be prepared 'when 3 to 6 moles of tetranitromethane are combined with one or more moles of carborane. However, stoichiometry of the reaction may be varied to produce nitrogen plus either CO or CO2 as the major gaseous products.

This invention is advantageous over the prior art in several respects in both its composition and process aspects. For example, in its composition aspect, this invention offers the advantage of an explosive system where neither of the uncombined components are separately hazardous yet the combined components quickly produce an explosive mixture. These explosive reaction mixtures generally have the ability to release more explosive energy on a weight by weight basis than that liberated by TNT under the same conditions.

In addition, many of the explosive reaction mixtures require no detonating device since they become increasingly sensitive to detonation with the passage of time. While exposive deivces exist which may be detonated by a timed device, no practical explosive system is available wherein the degree of shock sensitivity is dependent upon the passage of time alone. These explosive mixtures have wide application to anti-personnel mines and devices and are particularly suitable for partisan or underground warfare. As these explosive reaction mixtures are metalfree and need not be stored in metallic containers they are virtually impossible to detect by present detection means.

The explosive reaction mixtures of this invention are also substantially advantageous explosives compared to the individual reactants. For example, the carboranes by themselves are only marginally active lower power explosives and require a separate and additional detonating device. The polynitroalkanes as exemplified by tetranitromethane have several distinct disadvantages. These include low explosive force, erratic chemical interaction with the fuel component, the presence of a high proportion of -low boiling solvent(s), and a requirement for both additional detonating means and booster charges.

This invention in its process aspect offers some significant advantages over the prior art. These include among others, reactants which are either commercially available or can be readily prepared as previously described, mild reaction conditions, and the obviating of the need for hazardous detonating and booster devices.

To more fully set forth the inventive concepts intended to be within the scope of this invention, the following illustrative examples are submitted:

Example 1.--Preparation of an explosive reaction mixture of tetranitromethane and ll-isopropenylcarborane A. Preparation of 11-isopropenylcarborane-A mixture of 17.0 parts by weight of isopropenylacetylene, 50.0 parts by weight of bis (acetonitrilo) decaborane and 880 parts by weight of benzene is placed in a sealed pressure reactor and the agitated mixture is heated to 50 C. for 24 hours. At the end of this time the unreacted this( acetonitrilo) decaborane is filtered o and the product is obtained by evaporating thesolvent and recrystallizing from a methanol-water system.

B. Preparation of explosive reaction mixture-To a reactor containing 18.4 parts by weight of the ll-isopropenylcarborane product obtained in Part A, is added slowly 78.4 parts by weight of commercial grade tetranitromethane (a 1:4 mole ratio) and the mixture is agitated by bubbling a stream of nitrogen through it. A homogeneous solution results after a relatively short time.

The two components are mixed in accordance with the following stoichiometry:

The explosive power of this system is evaluated by a plate dent test. In this test a standard plate of metal is exposed to a measured quantity of explosive and detonated. The dent in the metal is measured. The depth of the dent is an indication of both detonatability and the power of the sample explosive. A standard sample of TNT gave a dent depth of 0.119, whereas the above mixture under the same test conditions has a plate dent value of 0.140", a significant improvement.

In standard impact sensitivity tests it is found that the H50 value of the explosive reaction mixture decreased, i.e., the sensitivity increased upon standing. 0

This test is a standard means of determining the sensitivity of an explosive to detonation by impact shock. In this procedure a standard weight is dropped from different heights onto the explosives to be evaluated. The H50 represents the minimum height at which the weight will detonate 50% of the replicate samples tested. After 24 hours it was 3 inches/2 kg. wt. for the mixture whereas nitroglycerin was 15% inches.

Example 2.-Preparation of a different explosive reaction mixture of tetranitromethane and ll-isopropenylcarborane The same techniques and reactants described in Example 1 are used, but the ratio of the two reactants is changed to balance the equation for CO2 rather than CO. The CO2 balanced equation is shown below:

Using the test procedure of Example 1, a plate dent value of 0.132" is obtained.

Example 3.-Preparation of an explosive reaction mixture of tetranitromethane and carborane A. Preparation of carborane (H-o C-H) Bwllo A charge of 11.60 parts lby weight of bis(acetoxymethyl) carborane and 200 parts by weight of 20% KOH is added to a reactor equipped with a heating, cooling and stirring means. To the stirred alkaline mixture kept at about 25 C., is added slowly 16.90 parts by weight of finely powdered KMnO4. The addition of the KMnO4 takes from 8-12 hours. After the addition is complete, the reaction mixture is cooled, acidified with HZSO., and then extracted three times using a total of 225 parts by weight of benzene. The benzene extracts are combined and dried under vacuum by weight of benzene.

B. Preparation of the explosive reaction mixture-A 17.3 parts by weight of carborane prepared as described in Part A is dissolved in 7.3 parts Iby weight of commercial grade nitromethane and the resultant solution is added to 10.3 parts by weight of commercial grade tetranitromethane. Homogeniety is achieved by agitation with a stream of nitrogen gas passed into the mixture. A portion of the explosive reaction mixture is subjected to the plate dent test used in Examplev 1 and a dent value of 0.137 is obtained. Under comparable conditions TNT gives a value of 0.119".

The H50 value of the mixture is 16% using a 7.6 lb. weight whereas nitroglycerin tested under the same conditions has a H50 value of 6% In this example the stoichiometry of the system is as shown below:

Example 4.-Preparation of other carborane-tetranitromethane explosive reaction mixtures The same reactants and techniques are used as in Example 2 but the stoichiometric ratios of the reactants are varied to form CO rather than CO2:

The quantities used are 1 part by weight of carborane for each 0.85 part by weight of nitrornethane and 4.7 parts by weight of tc-:tranitromethane` The plate dent value (0.131) of the resultant explosive reaction mixture is less than that obtained in Example 3, but is still significantly higher than 0.119" value obtained for TNT.

Example 5.-Preparation of an explosive reaction mixture of tetranitromethane and 1 1,12-bis-(hydroxymethyl) carborane, triuoroacetate esters A. Preparation of 11,12-bis-(hydroxymethyl)carborane-A l parts 'by weight portion of 11,12bis(hydroxy methyl)carborane derived from the acid hydrolysis of the reaction product of 1,4-diacetoxy-2-butyne and 6,9-bis (acetonitrilo) decaborane, is reuxed for 1 hour with 52 parts by weight of triiluoracetic anhydride. The resultant solution is distilled to yield parts yby weight of the triuoroacetate ester.

B. Preparation of the explosive reaction mixture-The explosive reaction mixture is prepared by mixing 23.8 parts by weight of the above ester with 60.8 parts by weight of tetranitromethane usiugra stream of nitrogen gas to bring about a homogeneous solution. The plate dent value is 0.142". The stoichiometry is believed as shown below, balanced to produce CO2.

Example 6,-Preparation of an explosive reaction mixture of tetranitromethane and 11, l2-bis (hydroxybutyl) carborane, trichloroacetate ester A. Preparation of 11,12-bis(hyroxybutyl) carborane.- A 10 parts by weight portion of 11,12-bis (hyroxyethyl) carborane derived from the acid hydrolysis of the reaction product of 1,6-diacetoxy-3-hexyue and 6,9 bis(ace tonitrilo) decaborane, is refluxed for 4 hours with 80 parts by weight of trichloroacetic acid in the presence of a trace of p-toluene sulfonic acid to form the trichloroacetate ester.

B. Preparation of explosive reaction mixture-The explosive reaction mixture is prepared by mixing 20.3 parts by weight of the above ester with 42.5 parts by weight of tetranitromethane. Mixing is accomplished by passing a stream of nitrogen through the reaction mixture for 10 minutes. The plate dent value is approximately .105. The equation is balanced to yield CO2, N2, B203, HC1, and H2O.

Example 7.- reparation of an explosive reaction mixture of tetranitromethane and ll-hydroxymethylcarborane, triuoroacetate ester A. Preparation of triuoroacetate ester of ll-hydroxymethyi-carborane.-A 10 parts by weight portion of 11- hydroxymethylcarborane is suspended in 30 parts by weight of tritluoroacetic anhydride and heated on the steam bath for l hour. The reaction mixture is reuxed for 1 hour to yield 11 parts by weight of the l1-triuoroacetoxymethylcarborane product.

B. Preparation of explosive reaction mixture-A 2O parts by weight/portion of the above prepared ester product is mixed thoroughly with 50 parts by weight of tetranitromethane using a stream of nitrogen gas as the mixing means. The plate dent value of the explosive reaction mixture is in excess of 0.119".

Example 8.-Preparation of an explosive reaction mixture of tetranitromethane and a butenyl carborane A. Preparation of n-butenylcarborane.-A mixture of 80 parts by weight of S-hexen-l-yne and 200 parts by weight of bis(acetonitrilo) decaborane and 1000 parts by weight of benzene is refluxed for 24 hours. At the end of this time the unreacted bis(acetonitrilo) decarborane is filtered off and the a-butenylcarboranes product is recovered by evaporating off the benzene under vacuum.

B. Preparation of the explosive reaction mixture- The The gelled product of above when analysed by infrared analysis indicated the presence of two distinct structures.

Biol-Ito and NoiCI-IztlHozHiC-TCH C (Nom Blot-1,0

The infra-red curves which are evidenciary of the structures described above are presented in the accompanying gures. FIGURE 1 shows the infrared spectrum of 11- (3-butenyl) carborane. FIGURE 2 shows the infrared spectrum of the teranitromethane reactant. FIGURE 3 shows the reaction product of oc-butenyl-carborane and tetranitromethane.

Example 9.-Preparation of an explosive reaction mixture of tetranitromethane and isopropylcarborane A. Preparation of isopropylcarborane.-A one-liter, three-necked ask, fitted with a Dry-Ice reflux condensor thermometer and agitator, is charged with 86 g. of isopropenylacetylene, 100 g. of decaborane, 169 g. of acetonitrile and 217 g. of toluene. The contents are vigorously stirred and the flask is heated and maintained at a temperature of about 65-70" C. (reflux) for 24 hours; at this time the solvents are stripped at C./760 mm. and nally at C./15 mm. The contents of the flask are then slowly added to 332 g. of pentane with rapid agitation at which point solids precipitated. The solids are removed by filtration, washed with pentane and the washings combined with the filtrate. The filtrate is washed with 10% by weight solution of caustic in water, then with water until neutral. The pentane removed by distillation. The residue, crude isopropenylcarborane, is isolated by rectification at 95-100 C./4 mm. The isopropenylcarborane is subsequently reduced to isopropylcarborane using a nickel catalyst and 50 pounds hydrogen pressure.

B. Preparation of the explosive reaction mixture-A 558.6 parts by weight portion of isopropylcarborane is combined with 2352 parts by weight of tetranitromethane and the reactants are mixed using a stream of argon gas. The explosive reaction mixture gives a plate dent value of 0.131.

Example 10,-Preparation of an explosive reaction mixture of tetranitromethane and methylcarborane A. Preparation of methylcarborane.-A two-litre autoclave, equipped with heating, cooling and stirring means is charged with 75 g. of bistacetonitrilo) decaborane, 400 ml. of benzene and 15.6 g. of l-propyne. The mixture is agitated and brought to reflux and maintained at temperatures of 12 hours. The mixture is allowed to cool filtered and the filtrate stripped olf to remove solvent. An oily residue remained, which is extracted with petroleum ether. The petroleum ether extract is stripped off and the residue purified by distillation at C./5 mm. to yield methylcarborane, a solid melting at 215 C.

B. Preparation of the explosive reaction mixture.- A 9.1 parts by weight of the above prepared methylcarborane is combined with 70.2 parts by weight of tetranitromethane and 20.7 parts by weight of nitromethane and the solutions mixed by passing a stream of nitrogen gas througli them. The stoichiometry of the system is balanced to produce CO2. The equation is shown below:

The plate dent value is 0.131. The

H50 value with a 7.6 pound weight was ,1/8".

Example 11.-Preparation of another explosive reaction mixture of tetranitromethane and methylcarborane Methylcarborane Nitromethane 46.5 Tetranitromethane 45.5

are mixed with a stream of nitrogen gas. The equation is balanced to produce CO and appears below.

The plate dent value is 0.137, the H50 value (2 kg. wt.) was 29 inches.

Example 12.--Preparation of an explosive reaction mixture of tetranitromethane and n-hexylcarborane A. Preparation of n-hexylcarborane.--A one-liter, three-necked liask equipped with a stirrer and reflux condenser is charged with 25 g. of bis(acetonitrolo) decaborane, 500 ml. of benzene and 14.1 g. of l-octyne. This mixture is agitated and brought to reflux and maintained at temperature for l2 hours. The mixture is allowed to cool, iiltered and the iiltrate stripped oli to remove solvent. An oily residue remained, which is extracted with petroleum ether. The petroleum ether extract is stripped off and the residue puriiied by distillation at 130 C /5 mm. to yield n-hexylcarborane.

B. Preparation of the explosive reaction mixture- Using the stirring techniques described previously 14.6 parts by weight of the above prepared n-hexylcarborane is thoroughly mixed with 103.2 parts by weight of tetranitromethane. The stoichiometry of the system was suc-h to form as products, CO2, H2O, B202, and N2. The plate dent value was equal to that of TNT.

Example 13.--Preparation of an explosive reaction mixture of tetranitromethane and n-octylcarborane A. Preparation of octylcarbonane.-A two liter autoclave, equipped with heating, cooling and stirring means is charged with 35 g. of bis(acetonitrilo) decaborane,

500 ml. of benzene and 17.2 g. of l-decyne. The mixture is agitated and brought to reflux and maintained at the reliux temperature for 14 hours. The mixture is allowed to cool, filtered and the filtrate stripped oi to remove solvent. The oily residue which remains is extracted twice with petroleum ether. The petroleum ether in the combined extracts is stripped off and the residue puried by distillation at 140 C./5 mm. the liquid product is the n-octylcarborane.

B. Preparation of the explosive reaction mixture.- Using the stirring techniques described previously 22.3 parts by weight of the above prepared octylcarborane is thoroughly mixed with 160.4 parts by Weight of tetranitromethane. The stoichiometry of the system produces CO2, H2O, B202 and N2. The plate dent value is between 0.l15-0.119 inches.

Example 14.-Preparation of an explosive mixture of tetranitromethane and ethylcarborane 500 ml. of benzene and 13.8 g. of l-butyne. The mixture is agitated and brought to reflux and maintained at the reflux temperature for 12 hours. The mixture is allowed 10 to cool, ltered and the filtrate stripped oit to remove solvent. An oily residue remained, which is extracted with petroleum ether. The petroleum ether extract is stripped off and the residue purified by distillation at C./S mm. to yield the solid ethylcarborane.

B. Preparation of the explosive reaction mixture.- Using the stirring techniques described previously, ethylcarborane was thoroughly mixed with sufcient tetranitromethane to produce CO2, H2O, B202, and N2. The plate dent value is about 0.125 inch.

Example 15.-Preparation of an explosive reaction mixture of tetranitroglycerin and carborane Carborane as prepared in Example 2 is combined with commercially obtained tetranitroglycerin in the stoichiometry of the system which favors the production of CO2, B202, H2O, and N2. The stirring techniques used are as previously described. The plate dent value exceeded the 0.119" obtained with TNT but was less than that obtained with the carborane tetranitromethane mixture in Example 2.

Example 16.Preparation of an explosive reaction mixture of tetranitroglycerin and ll-isopropenylcarborane Isopropenylcarborane prepared as in Example l is cornbined with commercially obtained tetranitroglycerin in a ratio that favors the production of CO2, B203, H2O, and N2. The stirring is by a stream of nitrogen gas as previously described. The plate dent value of the reaction mixture is superior to that obtained with TNT but is less than that obtained with the ll-isopropenylcarboranetetranitromethane reaction mixture of Example 1.

Example 17.-Preparation of an explosive reaction mixture of pentaerythritol tetranitrate and carborane Carborane as prepared in Example 3 is combined with commercially obtained pentaerythritol in a ratio stoichiometrically balanced to favor the production of CO2, B202, H2O and N2. The stirring and testing techniques are as previously described. The plate dent value approximates that obtained with TNT.

Example 18.-Preparation of an explosive reaction mixture of Pentaerythritol tetranitrate and isopropenylcarborane Isopropenylcarborane as prepared in Example 1 is combined with commercially obtained pentaerythritol tetranitrate in a ratio stoichiometrically balanced to produce CO2, B202, H2() and N2. The stirring and testing techniques are as previously described. The plate dent value is between 0.119 and 0.132.

It is to be clearly established that the foregoing samples are illustrative only and do not constitute the metes and bounds of this invention. For example, the ratio of reactants will determine not only the stoichiometry of the system, but will effect the quality and quantity of combustion products, the explosive force obtained as well as the impact sensitivity. Furthermore the test values can shift with even relatively slight changes or modications in the reaction conditions. The invention is best defined by the claims which follow:

We claim:

1. Liquid explosive reaction mixtures comprising polynitroaliphatic and carborane reactants.

2. The explosive reaction mixtures of claim 1 whe-rein the ratio of polynitroaliphatic and carborane 4reactants are stoichiometrically balanced to produce CO2.

3. The explosive reaction mixtures of claim 1 wherein the ratio of polynitroaliphatic and carborane reactants are stoichiometrically balanced to produce CO.

4. The react-ion mixture of claim 1 wherein the polynitroaliphatic reactant is tetranitromethane.

5. The reaction mixture of claim 1 wherein the polynitroaliphatic reactant is tetranit-roglycerin.

6. The reaction mixture of claim 1 wherein the polynitroaliphatie reactant is pentaerythritol tetranitrate.

7. Liquid explosive reaction mixtures comprising tetranitromethane and carborane reactants.

8. The react-ion mixture of claim 7 wherein the carborane reactant is carborane.

9. The reaction mixture of claim 7 wherein the ,carborane reactant is alkylcarborane.

10. The reaction mixture of claim 9 wherein the alkyl carborane is methylcarbor-ane.

11. The reaction mixture of claim 9 wherein the alkylcarborane is ethylcarborane.

12. The react-ion mixture of claim 9 wherein the alkylcarborane is propylcarborane.

13. The reaction mixture of claim 9 wherein the alkylcarborane is a pentylcarborane.

14. The reaction mixture of claim 9 wherein the alkylcarborane is a hexylcarborane.

15. The reaction mixture of claim 9 wherein the alkylcarborane is a heptylcarborane.

16. The reaction mixture of claim 9 wherein the alkylcarborane is octylcarborane.

17. The reaction mixture of claim 7 wherein the carborane reactant is an `alkenylcarborane.

18. The reaction mixture of claim 17 wherein the alkenylcarborane is isopropenylcarborane.

19. The reaction mixture of claim 16 wherein the alkylcarborane -is a-butenylcarbor-ane.

20. The reaction mixture of claim 7 wherein the carborane reactant is a hydroxylalkylcarborane.

21. Liquid explosion reaction mixtures of tetranitromethane and hydroxymethylcarborane.

22. The liquid explosive reaction mixtures of claim 21 wherein the ratio of the reactants `are stochiometrically balanced to produce CO2.

23. The liquid explosive reaction mixtures of claim 21 wherein the ratio of the reactants are stoichiometrically balanced to produce CO.

24. The liquid explosive reaction mixture comprising a major amount of polynitroaliphatic and carborane reactants with a mononitroparaftn.

27. The process of preparing liquid explosive reaction mixtures comprising, contacting polynitroaliphatic and carborane reactants until a substantially homogeneous reaction mixture results, said reactants being present in proportions ranging from 1/s to 2 times the theoretical stoichiometric ratios required to form gaseous combustion products.

28. The process of claim 27 wherein the two reactants are present in proportions ranging from 1/5 to 2 times the theoretical stoichiometric ratios required to form CO2.

29. The process of claim 27 wherein the two reactants are present in proportions ranging from 1/5 to 2 times the theoretical stoichiometric ratios required to form CO.

30. The process of claim 27 wherein the polynitroaliphatic reactant is tetranitromethane.

31. The process of claim 27 wherein the polynitroaliphatic reactant is tetranitroglycerin.

32. The process of claim 27 wherein the polynitroaliphatic reactant is pentaerythritol tetranitrate.

33. The process of claim 27 wherein the reactants are tetranitromethane and an alkylcarborane.

34. The process of claim 33 wherein the reactants are tetranitromethane and propylcarborane.

35. The process of claim 27 wherein the reactants are tetranitromethane and an alkenylcarborane.

36. The process of claim 35 wherein the alkenyl reactant is isopropenylcarborane.

37. The process of preparing stabilized liquid explosive reaction mixtures comprising, contacting a major amount of polynitrated aliphatic and carborane reactant and a minor amount of a mononitrated paraffin stabilizer until a homogenous reaction mixture is formed, said major reactauts being present in proportions ranging from 1/5 to 2 times the theoretical stoichiometric ratio required to form lgaseous combustion products.

38. The process of claim 37 wherein the stabilizer is nitromethane.

39. The process of claim 38 wherein the stoichiometric ratio of the reactants is -balanced to produce CO2.

40. The process of claim 38 wherein the stoichiometric ratio of the reactants is balanced to produce CO.

41. Stabilized liquid explosive compos-ition comprising a homogeneous mixture of a major amount of a polynitroaliphatic Vreactant and a car-borane reactant `and ya minor amount of a mononitrated parain stabilizer, said major reactants being present in proportions ranging from 1/s to 2 times the theoretical stoichiometric ratios required to form gaseous products.

42. The stabilized explosive compositions of claim 41 wherein the stabilizer is nitromethane.

43. The stabilized explosive compositions of claim 42 wherein the stoichiometric ratio of the major reactants is balanced to produce CO2.

44. The stabilized explosive compositions of claim 42 wherein the stoichiometric ratio of the major reactants is balanced to produce CO.

45. The stabilized compositions of claim 43 wherein the polynitroaliphatic reactant is tetranitromethane and the carborane reactant is an alkylcarborane.

46. The stabilized compositions of the claim 45 wherein the alkylcarborane is methylcarborane.

References Cited UNITED STATES PATENTS 7/1963 Tyson 149-22 2/1964 Clark 260-467 

41. STABILIZED LIQUID EXPLOSIVE COMPOSITION COMPRISING A HOMOGENEOUS MIXTURE OF A MAJOR AMOUNT OF A POLYNITROALIPHATIC REACTANT AND A CARBORANE REACTANT AND A MINOR AMOUNT OF A MONONITRATED PARAFFIN STABILIZER, SAID MAJOR REACTANTS BEING PRESENT IN PROPORTIONS RANGING FROM 1/5 TO 2 TIMES THE THEORETICAL STOCHIMETRIC RATIOS REQUIRED TO FORM GASEOUS PRODUCTS. 